UNITED NATIONS — The U.N. General Assembly urged Israel and the Palestinians Thursday to investigate alleged war crimes during last winter's conflict in Gaza and raised the possibility of Security Council action if they don't.

The 192-member world body approved an Arab-drafted resolution by a vote of 114-18, with 44 abstentions and 16 countries not voting.

Supporters insisted there must be accountability — especially from Israel — for the alleged violations of international law during the Gaza conflict in which 13 Israelis and almost 1,400 Palestinians were killed, including many civilians.

Israel rejected the resolution as "deeply flawed, one-sided and prejudiced" while the United States called it "unbalanced and biased" and warned that it will hurt prospects for achieving Mideast peace. Others voting "no" included Australia, Canada, Germany, Italy, Panama and a number of other European and Pacific island states.

Riyad Mansour, the Palestinian U.N. observer called it "an important night in the history of the General Assembly and the history of fighting against impunity and seeking accountability."

The resolution "endorses" a report by an expert panel chaired by South African Judge Richard Goldstone which concluded that both Israel and Palestinian militants committed war crimes and possible crimes against humanity during the Gaza war.

The report concluded that Israel used disproportionate force, deliberately targeting civilians, using Palestinians as human shields, and destroying civilian infrastructure during the incursion to root out Palestinian rocket squads targeting southern Israel.

It accused Palestinian armed groups of deliberately targeting civilians and trying to spread terror through its rocket attacks on southern Israel. Hamas, the main rival to the Palestinian Authority which Mansour represents, controls Gaza and most armed groups in the territory.

Many Western nations that voted against the resolution or abstained said they did not endorse all the recommendations in the 575-page Goldstone report, and opposed the possibility of Security Council action.

The resolution urges Israel and "the Palestinian side" to conduct "independent, credible" investigations within three months.

It asks Secretary-General Ban Ki-moon to report to the General Assembly, within three months, on implementation by both sides "with a view to considering further action, if necessary, by the relevant United Nations organs and bodies, including the Security Council."

Unlike Security Council resolutions, General Assembly resolutions are not legally binding but they do reflect the views of the broader U.N. membership.

Mansour said the Palestinians will return to the General Assembly in three months to consider the secretary-general's report "with a view for further action."

He said at the start of the assembly's two-day debate on Wednesday that the Palestinians will pursue justice for Palestinian victims in the Security Council and at the International Criminal Court, the world's permanent war crimes tribunal.

"We started the journey today ... and we will continue this process until we make sure that the Israeli criminals who have committed war crimes against the Palestinian civilians face justice and get the punishment they deserve," Mansour said.

The resolution also calls on Switzerland to reconvene a meeting of the parties to the Fourth Geneva Convention, which spells out the obligations of an occupying power, and Mansour said the Palestinians will start preparing for this.

Before the vote, Israel's deputy U.N. ambassador Daniel Carmon demanded to know who would conduct a Palestinian investigation — the Palestinian Authority "that was ousted from Gaza in a violent coup" or "the Hamas terrorist organization ... which rejects the recognition of Israel."

Egypt's U.N. Ambassador Maged Abdelaziz, who introduced the resolution, replied that "the Palestinian Authority itself declared that they are going to conduct their own investigation" and Hamas has "already expressed the willingness to cooperate and to investigate and to prosecute those that are going to be responsible for these crimes."

Abdelaziz then asked Carmon if Israel will conduct a similar independent investigation, adding: "I think that this will be very happy news to the General Assembly."

Carmon replied that "Israel has been conducting professional, credible and thorough investigations as part of its standard operating procedures, and irrespective of any U.N. report" and went on to denounce the resolution.

"It disregards Israel's inherent right to defend its citizens in the face of ongoing terrorist attacks," he said. "It represents yet another pretext to bash Israel at the U.N. and is detrimental to any positive diplomatic engagement in the region."

U.S. deputy ambassador Alejandro Wolff told the assembly that "the United States strongly supports accountability for human rights and humanitarian law violations in relation to the Gaza conflict" and will continue to call for all parties to pursue credible domestic investigations.

But he strongly criticized the Goldstone report for "its unbalanced focus on Israel" and its "failure to assign appropriate responsibility to Hamas for its decision to base itself and its operations in heavily civilian-populated urban areas." He reiterated that the U.S. believes the report should remain in the Geneva-based Human Rights Council, which commissioned it.

The General Assembly action came two days after the U.S. House of Representatives passed a nonbinding resolution by a vote of 344-36 condemning the Goldstone report as "irredeemably biased and unworthy of further consideration or legitimacy." Goldstone sent the House Foreign Affairs Committee a 16-point rebuttal of what he said were incorrect or unfair readings of his report in the resolution.